Secondary battery and method for manufacturing the same

Abstract

The present disclosure relates to a secondary battery and a method for manufacturing the same. The technical problem to be solved is to provide a secondary battery and a method for manufacturing the same that can be manufactured by only bending after welding, thereby improving assembly, forming a wide welding area, and allowing all tabs to be welded to a connecting member, thereby improving heat dissipation performance due to reduced resistance. To this end, the present disclosure provides a secondary battery characterized by comprising: a case; an electrode assembly disposed inside the case and having a first electrode and a second electrode; a first tab member connected to the first electrode and extending from the electrode assembly; a cap assembly disposed facing the electrode assembly and having a first terminal and a second terminal; a first connecting member electrically connecting the first terminal of the cap assembly and the first tab member; and a first connecting hole formed in the first tab member to allow the first connecting member to be inserted.

Description

Technology Field

[0001] The present disclosure relates to a secondary battery and a method for manufacturing the same. Background Technology

[0003] In general, the demand for high-energy-density, high-capacity rechargeable batteries is rapidly increasing in line with the recent rapid proliferation of battery-powered electronic devices such as mobile phones, laptop computers, and electric vehicles. Accordingly, research and development to improve the performance of lithium-ion batteries is actively underway.

[0004] A lithium secondary battery is a battery comprising a positive electrode and a negative electrode containing an active material capable of lithium ion intercalation and deintercalation, and an electrolyte, and produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated / deintercalated from the positive electrode and the negative electrode.

[0005] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art. The problem to be solved

[0007] The purpose of the present invention is to provide a secondary battery and a method for manufacturing the same, which can be manufactured by bending only after welding to improve assembly, form a wide welding area, and improve heat dissipation performance by reducing resistance by allowing all tabs to be welded to a connecting member.

[0008] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below. means of solving the problem

[0010] A secondary battery according to an embodiment of the present invention for solving the above technical problem comprises: a case; an electrode assembly disposed inside the case and having a first electrode and a second electrode; a first tab member connected to the first electrode and extending from the electrode assembly; a cap assembly disposed facing the electrode assembly and having a first terminal and a second terminal; a first connection member electrically connecting the first terminal of the cap assembly and the first tab member; and a first connection hole formed in the first tab member to allow the first connection member to be inserted.

[0011] The first tab member may be composed of a pair spaced apart on one side with respect to the center of the first electrode.

[0012] The first tab member is formed on one side based on the center of the first electrode, and a plurality of first connection holes may be formed in the first tab member.

[0013] The first connecting member comprises a first portion disposed on one side with respect to the center of the first connecting member and electrically connected to the first terminal; and a second portion disposed on the other side with respect to the center of the first connecting member and inserted into the first connecting hole, wherein the first connecting member is bent with respect to the center of the first connecting member so that the first portion can be folded over the upper part of the second portion.

[0014] The above second portion can be welded to the first tab member while inserted into the first connection hole.

[0015] The first tab member can be compacted while the second portion is inserted into the first connection hole.

[0016] With the above-mentioned second portion inserted into the above-mentioned first connection hole, a conductive bond can be filled inside the above-mentioned first connection hole.

[0017] The first portion above may be formed by bending vertically from the second portion.

[0018] An auxiliary tab that reinforces the rigidity of the welded portion may be further provided on the upper part of the first tab member.

[0019] A conductive adhesive may be applied to the upper surface of the above auxiliary tab.

[0020] It may include a detachment prevention member that prevents the first connecting member inserted into the first connecting hole from detaching.

[0021] The above anti-detachment member may be a hook formed at the end of the first connecting member and connected to the auxiliary tab.

[0022] The first connecting member may be composed of a plurality of thin tabs.

[0023] It may include a second tab member connected to the second electrode and spaced apart from the first tab member; a second connecting member electrically connecting the second terminal of the cap assembly and the second tab member; and a second connecting hole formed in the second tab member to allow the second connecting member to be inserted.

[0024] A method for manufacturing a secondary battery according to the present invention may include: a connection hole forming step of forming a connection hole in a tab member extending from an electrode assembly; a connection step of inserting a connection member connected to a terminal of a cap assembly into the connection hole; a welding step of electrically connecting the terminal and the tab member by welding the connection member and the tab member while the connection member is inserted into the connection hole; and a bending step of bending the center of the connection member so that the cap assembly is positioned on top of the tab member.

[0025] The above connection step may include a bond filling step of filling a conductive bond inside the connection hole while the connection member is inserted into the connection hole.

[0026] The above connection step may further include a compaction step in which the tab member is compacted while the connection member is inserted into the connection hole.

[0027] In the above welding step, an auxiliary tap is provided on the upper part of the tap member, and the upper part of the auxiliary tap is welded so that the auxiliary tap, the tap member, and the connecting member can be welded.

[0028] After the welding step above, a conductive bond may be applied to the upper surface of the auxiliary tab.

[0029] In the above bending step, the first portion connected to the terminal by bending with respect to the center of the tab member can be folded upwards toward the second portion inserted into the connection hole. Effects of the invention

[0031] According to an embodiment of the present invention, the secondary battery can be manufactured by bending only the connecting member after welding, thereby improving assembly performance.

[0032] According to an embodiment of the present invention, the size of the tab member can be increased, and all tab members can be welded to the connecting member, thereby improving heat dissipation performance due to reduced resistance.

[0033] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below. Brief explanation of the drawing

[0035] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention. FIG. 4 is a diagram schematically showing the configuration of an electrode assembly according to the first embodiment of the present invention. FIG. 5 is an enlarged view schematically showing the configuration of a cap assembly according to the first embodiment of the present invention. FIG. 6 is a front view schematically showing a tab member of an electrode assembly according to a first embodiment of the present invention. FIG. 7 is a first modified example schematically showing a tab member according to a first embodiment of the present invention. FIG. 8 is a second modified example schematically showing a tab member according to the first embodiment of the present invention. FIG. 9 is a third modified example schematically showing a tab member according to the first embodiment of the present invention. FIG. 10 is a drawing showing the connection between a first connecting member and a first tap member according to a first embodiment of the present invention. FIG. 11 is a first modified example showing the connection between a first connecting member and a first tab member according to a first embodiment of the present invention. FIG. 12 is a second modified example showing the connection between the first connecting member and the first tab member according to the first embodiment of the present invention. FIG. 13 is a schematic diagram showing the formation process of a secondary battery according to the first embodiment of the present invention. FIG. 14 is a schematic diagram showing the completed state of a secondary battery according to the first embodiment of the present invention. FIG. 15 is a first modified example schematically showing a first connecting member according to a first embodiment of the present invention. FIG. 16 is a second modified example schematically showing a first connecting member according to a first embodiment of the present invention. FIG. 17 is a schematic diagram showing the formation process of a secondary battery according to a second embodiment of the present invention. FIG. 18 is a schematic diagram showing the completed state of a secondary battery according to a second embodiment of the present invention. FIG. 19 is a modified example showing the connection between the first connecting member and the first tab member according to the second embodiment of the present invention. FIG. 20 is a schematic diagram showing the formation process of a secondary battery according to the third embodiment of the present invention. FIG. 21 is a schematic diagram showing the completed state of a secondary battery according to the third embodiment of the present invention. FIG. 22 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment of the present invention. Specific details for implementing the invention

[0036] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor may appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention; thus, various equivalents and modifications that can replace them may exist at the time of filing this application. Furthermore, as used in this specification, "comprise" or "include" and / or "comprising" or "including" specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups. In addition, when describing embodiments of the present invention, "may" and "may be" may include "one or more embodiments of the present invention."

[0037] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0038] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0039] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0040] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0041] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0042] Furthermore, where it is stated that one component is "connected," "coupled," or "connected" to another component, it should be understood that while said components may be directly connected or connected to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "connected" through another component. Additionally, when it is stated that a part is electrically coupled with another part, this includes not only cases where they are directly connected but also cases where they are connected with an intermediate element in between.

[0043] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise. That is, "and / or" includes any combination or any combination of the enumerated items. "C to D" means C or more and D or less, unless specifically stated otherwise.

[0044] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0045] The term "use" may be considered synonymous with the term "utilize." As used herein, "substantially," "about," and similar terms are used as terms of approximation rather than degree, and are intended to account for the inherent variation of measured or calculated values ​​that a person skilled in the art would recognize.

[0046] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0047] Spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used herein for ease of explanation to describe the relationship between one element or feature and another element(s) or feature(s) as illustrated in the drawings. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, an element described as "below" or "below" is understood as "above" or "upper" of another element. Thus, the term "below" may encompass both the up and down directions.

[0048] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0049] FIG. 1 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, and FIG. 3 is a cross-sectional view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention.

[0050] In the following description, the secondary battery is described as a prismatic battery as a lithium-ion secondary battery. However, the present invention is not limited thereto, and the secondary battery may be a lithium polymer battery or a cylindrical battery.

[0051] Referring to FIGS. 1 to 3, the secondary battery according to the present embodiment may include a case (100), an electrode assembly (200), a first tab member (310), a cap assembly (400), and a first connecting member (500).

[0052] The case (100) forms the general outline of the secondary battery and can accommodate the electrode assembly (200).

[0053] The case (100) according to the present embodiment may include a bottom portion (110), a front portion (120), a rear portion (130), a first side portion (140), and a second side portion (150).

[0054] The bottom portion (110) can form the lower (based on FIG. 3) exterior of the case (100). The bottom portion (110) according to the present embodiment may have the shape of a rectangular plate.

[0055] The front portion (120), rear portion (130), first side portion (140), and second side portion (150) can form the periphery surface of the case (100).

[0056] According to the present embodiment, the front portion (120), rear portion (130), first side portion (140), and second side portion (150) may have the shape of a plate extending upward from the edge of the bottom portion (110) (based on FIG. 2). The front portion (120), rear portion (130), first side portion (140), and second side portion (150) may be arranged to surround the upper space of the bottom portion (110). The front portion (120), rear portion (130), first side portion (140), and second side portion (150) may be arranged to form a rectangular cross-sectional shape.

[0057] The front section (120) and the rear section (130) may be arranged facing each other along the length direction. The front section (120) and the rear section (130) may be arranged parallel to each other. The areas of the front section (120) and the rear section (130) may be equal to each other.

[0058] The first side section (140) and the second side section (150) may be arranged facing each other along the width direction. The first side section (140) and the second side section (150) may be arranged parallel to each other. The areas of the first side section (140) and the second side section (150) may be equal to each other. The areas of the first side section (140) and the second side section (150) may be smaller than the areas of the front section (120) and the rear section (130).

[0059] The case (100) may further include an opening (160). The opening (160) according to the present embodiment may refer to a space enclosed by the upper portions of the front portion (120), rear portion (130), first side portion (140), and second side portion (150). The opening (160) may interconnect the internal space and the external space of the case (100).

[0060] Accordingly, the case (100) according to the present embodiment may have the shape of a rectangular prism with an open top.

[0061] The first direction described below may mean a direction parallel to the Z-axis with respect to FIGS. 2 and FIGS. 3, extending from the bottom portion (110) toward the opening portion (160). The second direction may mean a direction parallel to the Y-axis with respect to FIGS. 2 and FIGS. 3, extending from the first side portion (140) toward the second side portion (150). The third direction may mean a direction parallel to the X-axis with respect to FIGS. 2 and FIGS. 3, extending from the front portion (120) toward the rear portion (130).

[0062] The electrode assembly (200) can function as a unit structure that performs charging and discharging operations of power in a secondary battery. The electrode assembly (200) can be accommodated inside the case (100).

[0063] FIG. 4 is a diagram schematically showing the configuration of an electrode assembly according to one embodiment of the present invention.

[0064] Referring to FIGS. 1 to 4, the electrode assembly (200) according to the present embodiment may include a first electrode (210), a second electrode (220), and a separator (230) disposed between the first electrode (210) and the second electrode (220). The first electrode (210), the separator (230), and the second electrode (220) may be provided in multiple numbers.

[0065] Hereinafter, the electrode assembly (200) will be described as having a stacked form in which a plurality of first electrodes (210), separators (230), and second electrodes (220) are sequentially stacked along a third direction. However, the electrode assembly (200) is not limited to such a form, and it is also possible to form a shape in which the first electrode (210), separator (230), and second electrode (220) are stacked and wound along a clockwise or counterclockwise direction around a winding axis (C).

[0066] The first electrode (210) can function as either the positive or negative electrode of the electrode assembly (200). Hereinafter, the first electrode (210) will be described as an example of being the positive electrode of the electrode assembly (200). However, the first electrode (210) is not limited to this, and it is also possible for it to function as the negative electrode of the electrode assembly (200).

[0067] The first electrode (210) according to the present embodiment may be formed to have the shape of a foil including a metal material such as aluminum or an aluminum alloy. As long as the first electrode (210) is conductive without causing chemical changes in the secondary battery, its type, size, and shape are not particularly limited. The cross-sectional shape of the first electrode (210) can be designed to have various shapes other than the rectangle shown in FIG. 4.

[0068] The first electrode (210) may be provided in multiple numbers. The multiple first electrodes (210) may be arranged along a third direction between the front portion (120) and the rear portion (130) of the case (100). The number of first electrodes (210) can be varied in design depending on the charging capacity of the secondary battery, etc.

[0069] A first active material layer (211) may be applied to at least a portion of the first electrode (210). The first active material layer (211) may be applied to both sides of the first electrode (210), or alternatively, it may be applied to only one side of the first electrode (210).

[0070] In this embodiment, as the first electrode (210) functions as a positive electrode, the first active material layer (211) may include a positive electrode active material.

[0071] The cathode active material may be a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound). More specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, iron, and combinations thereof may be used.

[0072] For example, the positive electrode active material may include at least one of lithium-iron-phosphorus oxide (LiFePO4, LFP), lithium-manganese-iron-phosphorus oxide (LiMnFePO4, LMFP), and lithium-nickel-cobalt-manganese oxide (LiNixCoyMnzO2, NCM). Here, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1을 만족할 수 있다. 양극 활물질은 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM) 중 어느 하나만을 포함할 수 있고, 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM)중 어느 두개 또는 이들을 모두 포함하는 것도 가능하다.

[0073] The first active material layer (211) may further include an anode conductive material.

[0074] The positive electrode conductive material is used to impart conductivity to the first active material layer (211), and any electronically conductive material that does not cause chemical changes can be used. Examples of positive electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc., metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0075] The first active material layer (211) may further include an anode binder.

[0076] The positive binder serves to adhere the particles constituting the positive active material well to each other and also to adhere the positive active material well to the first electrode (210).

[0077] Examples of positive binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0078] Examples of non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0079] The water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0080] When using a water-based binder as the anode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0081] The dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0082] The first electrode (210) may include a first blank portion (212) where the first active material layer (211) is not applied. The first blank portion (212) according to the present embodiment may be disposed in an upper portion of the first electrode (210) positioned to face the opening (160) inside the case (100). However, the first blank portion (212) is not limited to this shape and may also be formed over the entire edge portion of the first electrode (210).

[0083] The second electrode (220) can function as either the positive or negative electrode of the electrode assembly (200). Below, the second electrode (220) is described as the negative electrode of the electrode assembly (200) as an example. However, the second electrode (220) is not limited to this, and it is also possible for it to function as the positive electrode of the electrode assembly (200).

[0084] The second electrode (220) may be provided in multiple numbers. Multiple second electrodes (220) may be arranged along a third direction between the front portion (120) and the rear portion (130) of the case (100). The first electrode (210) and the second electrode (220) may be arranged alternately along the third direction. The second electrode (220) may be spaced apart from the first electrode (210) by a predetermined distance along the third direction.

[0085] The second electrode (220) according to the present embodiment may be formed to have the shape of a foil containing a metal material such as copper, copper alloy, nickel, or nickel alloy. The type, size, and shape of the second electrode (220) are not particularly limited as long as it is conductive without causing chemical changes in the secondary battery. The cross-sectional shape of the first electrode (210) can be designed to have various shapes other than the rectangle shown in FIG. 5.

[0086] A second active material layer (221) may be applied to at least a portion of the second electrode (220). The second active material layer (221) may be applied to both sides of the second electrode (220), or alternatively, it may be applied to only one side of the second electrode (220).

[0087] As the second electrode (220) functions as a negative electrode, the second active material layer (221) may include a negative active material.

[0088] The negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0089] Materials capable of reversibly intercalating / deintercalating lithium ions may include carbon-based negative electrode active materials, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0090] As lithium metal alloys, alloys of lithium and metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0091] As materials capable of doping and undoping lithium, Si-based negative electrode active materials or Sn-based negative electrode active materials may be used. Si-based negative electrode active materials may be silicon, silicon-carbon composites, SiOx (0 < x < 2), Si-Q alloys (wherein Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or combinations thereof. Sn-based negative electrode active materials may be Sn, SnO2, Sn-based alloys, or combinations thereof.

[0092] A silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0093] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0094] Si-based or Sn-based negative electrode active materials can be used in combination with carbon-based negative electrode active materials.

[0095] The second active material layer (221) may further include a negative electrode conductive material and a negative electrode binder.

[0096] The cathode conductive material is used to impart conductivity to the second active material layer (221), and any electronically conductive material that does not cause chemical changes can be used. Examples of cathode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc., metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0097] The negative electrode binder serves to adhere the particles constituting the negative electrode active material well to each other and also to adhere the negative electrode active material well to the second electrode (220).

[0098] Examples of cathode binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0099] Examples of non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0100] The water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0101] When a water-based binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0102] The dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0103] The second electrode (220) may include a second blank portion (222) where the second active material layer (221) is not applied. The second blank portion (222) according to the present embodiment may be positioned in the upper portion of the second electrode (220) positioned to face the opening (160) inside the case (100). However, the second blank portion (222) is not limited to this shape and may also be formed over the entire edge portion of the second electrode (220).

[0104] A separator (230) may be placed between the first electrode (210) and the second electrode (220). The separator (230) may perform the function of preventing a short circuit between the first electrode (210) and the second electrode (220) while allowing the movement of lithium ions between the first electrode (210) and the second electrode (220).

[0105] The separator (230) can be positioned to completely cover the surface area of ​​the electrode assembly (200). Accordingly, the separator (230) can prevent the first electrode (210) and the second electrode (220) from being directly exposed to the outside of the electrode assembly (200).

[0106] As such a separator (230), polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer membrane of two or more layers thereof may be used, and a mixed multilayer membrane such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0107] The separator (230) may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0108] The porous substrate may be a polymer membrane formed from any one of the following: polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacetal; polyamide; polyimide; polycarbonate; polyetherketone; polyaryletherketone; polyetherimide; polyamideimide; polybenzimidazole; polyethersulfone; polyphenylene oxide; cyclic olefin copolymer; polyphenylene sulfide; polyethylene naphthalate; glass fiber; Teflon; and polytetrafluoroethylene, or a copolymer or mixture of two or more of these.

[0109] The organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0110] Inorganic substances include Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include, but is not limited to, inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0111] Organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0112] The first tab member (310) is connected to the first electrode (210) and may protrude to the outside of the electrode assembly (200). As the first electrode (210) is exemplified as a positive electrode, the first tab member (310) may function as a positive electrode tab of a secondary battery. However, the first tab member (310) is not limited thereto, and when the first electrode (210) is a negative electrode, it may function as a negative electrode tab of a secondary battery.

[0113] The first tab member (310) according to the present embodiment may extend along a first direction from the electrode assembly (200). That is, the first tab member (310) may extend toward the opening (160) inside the case (100).

[0114] The first tab member (310) according to the present embodiment may be made up of a pair.

[0115] In this embodiment, the first tab member (310) is shown as being formed as a pair and extending along the first direction, but is not limited thereto and may also extend along the second direction and may be connected to the first connecting member (500) described later.

[0116] The first tab member (310) according to the present embodiment may have the shape of a foil extending along a first direction from the first blank portion (212) of the first electrode (210). The first tab member (310) may have a roughly rectangular shape. However, the shape of the first tab member (310) is not limited thereto, and the design can be modified into various shapes.

[0117] The first tap member (310) may be formed integrally with the first electrode (210). For example, the first tap member (310) may be the remaining area of ​​the first blank portion (212) after a portion of the first blank portion (212) has been cut or removed by notching or the like. Alternatively, the first tap member (310) may be manufactured separately from the first electrode (210) and then connected to the first blank portion (212) by welding or the like. The material of the first tap member (310) may be the same as the material of the first electrode (210).

[0118] The first tab member (310) may be provided in multiple numbers. The number of first tab members (310) may be equal to the number of first electrodes (210). Each first tab member (310) may extend individually from the first non-removable portion (212) of different first electrodes (210). Adjacent first tab members (310) may be arranged to face each other along a third direction. Adjacent first tab members (310) may be arranged parallel to each other. Accordingly, the first tab member (310) according to the present embodiment may be an assembly of multiple first tab members (310) stacked along a third direction. Adjacent first tab members (310) may be in contact with each other, and may also be spaced apart by the thickness of the separator (230).

[0119] The secondary battery according to the present embodiment may further include a second tab member (330).

[0120] The second tab member (330) is connected to the second electrode (220) and may protrude to the outside of the electrode assembly (200). As the second electrode (220) is exemplified as a negative electrode, the second tab member (330) may function as a negative electrode tab of a secondary battery. However, the second tab member (330) is not limited thereto, and if the second electrode (220) is a positive electrode, it may function as a positive electrode tab of a secondary battery.

[0121] The second tab member (330) according to the present embodiment may extend along a first direction from the electrode assembly (200). That is, the second tab member (330) may extend toward the opening (160) inside the case (100).

[0122] The first tap member (310) and the second tap member (330) may be spaced apart along the second direction. For example, the second tap member (330) may be positioned at a predetermined distance from the first tap member (310) along the second direction.

[0123] The second tab member (330) according to the present embodiment may be made up of a pair.

[0124] In this embodiment, the second tab member (330) is shown as being formed as a pair and extending along the first direction, but is not limited thereto and may also extend along the second direction and may be connected to the second connecting member (600) described later.

[0125] The second tab member (330) according to the present embodiment may have the shape of a foil extending along the first direction from the second blank portion (222) of the second electrode (220). The second tab member (330) may have a roughly rectangular shape. However, the shape of the second tab member (330) is not limited thereto, and the design can be modified into various shapes.

[0126] The second tap member (330) may be formed integrally with the second electrode (220). For example, the second tap member (330) may be the remaining area of ​​the second blank portion (222) after a portion of the second blank portion (222) has been cut or removed by notching or the like. Alternatively, the second tap member (330) may be manufactured separately from the second electrode (220) and then connected to the second blank portion (222) by welding or the like. The material of the second tap member (330) may be the same as the material of the second electrode (220).

[0127] The second tab member (330) may be provided in multiple numbers. The number of second tab members (330) may be equal to the number of second electrodes (220). Each second tab member (330) may extend individually from the second non-removable portion (222) of a different second electrode (220). Adjacent second tab members (330) may be arranged to face each other along a third direction. Adjacent second tab members (330) may be arranged parallel to each other. Accordingly, the second tab member (330) according to the present embodiment may be an assembly of multiple second tab members (330) stacked along a third direction. Adjacent second tab members (330) may be in contact with each other, and may also be spaced apart by the thickness of the separator (230).

[0128] The cap assembly (400) is coupled to the case (100) and can seal the case (100). The cap assembly (400) can be positioned to face the electrode assembly (200) along a first direction.

[0129] FIG. 5 is an enlarged view schematically showing the configuration of a cap assembly according to one embodiment of the present invention.

[0130] Referring to FIGS. 1 to 5, the cap assembly (400) according to the present embodiment may include a cap plate (410), a first terminal (420), and a second terminal (430).

[0131] The cap plate (410) forms the general appearance of the cap assembly (400) and can support the first terminal (420) and the second terminal (430) in their entirety.

[0132] The cap plate (410) according to the present embodiment may be formed to have the shape of a flat plate. The cap plate (410) may be placed in the opening (160) of the case (100). The cap plate (410) may be placed facing the electrode assembly (200) along a first direction. That is, the cap plate (410) may be placed at a position spaced a predetermined distance from the electrode assembly (200) in the first direction. The cap plate (410) may be placed parallel to the bottom portion (110) of the case (100).

[0133] The cap plate (410) can be seated on the upper part of the case (100), more specifically, on the upper part of the front part (120), rear part (130), first side part (140), and second side part (150). The cap plate (410) can be attached to the case (100) by various types of joining methods, such as welding, bolting, and snap-fitting.

[0134] The first terminal (420) may protrude outward from the cap plate (410). The first terminal (420) may be electrically connected to the first electrode (210). As the first electrode (210) according to the present embodiment functions as a positive electrode, the first terminal (420) may be exemplified as a positive electrode terminal of a secondary battery.

[0135] The first terminal (420) according to the present embodiment may be inserted into the interior of the cap plate (410). The upper portion of the first terminal (420) may protrude along a first direction from the cap plate (410). Although FIG. 2 illustrates the first terminal (420) having a square cross-sectional shape as an example, the cross-sectional shape of the first terminal (420) is not limited thereto and can be designed to have various shapes such as a circle, ellipse, or polygon. The first terminal (420) may be formed from an electrically conductive material such as aluminum, nickel, copper, etc.

[0136] A first terminal shaft penetrating the central portion of the first terminal (420) in a first direction can be positioned between a pair of first tab members.

[0137] A first gasket (421) may be installed between the cap plate (410) and the first terminal (420). The first gasket (421) electrically insulates the cap plate (410) and the first terminal (420) and can block moisture or foreign substances from entering between the cap plate (410) and the first terminal (420).

[0138] The first gasket (421) according to the present embodiment may be formed from an insulating material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) rubber, etc. The first gasket (421) may be fixed between the cap plate (410) and the first terminal (420) by press fitting, injection molding, bonding, etc.

[0139] The second terminal (430) may protrude outward from the cap plate (410) at a position spaced apart from the first terminal (420). The second terminal (430) may be electrically connected to the second electrode (220). As the second electrode (220) according to the present embodiment functions as a negative electrode, the second terminal (430) may be exemplified as a negative terminal of a secondary battery.

[0140] The second terminal (430) according to the present embodiment may be inserted into the interior of the cap plate (410). The upper portion of the second terminal (430) may protrude along the first direction from the cap plate (410). Although FIG. 2 illustrates the second terminal (430) having a square cross-sectional shape as an example, the cross-sectional shape of the second terminal (430) is not limited thereto and can be designed to have various shapes such as a circle, ellipse, or polygon. The second terminal (430) may be formed from an electrically conductive material such as aluminum, nickel, copper, etc.

[0141] The second terminal (430) may be positioned at a predetermined distance from the first terminal (420) along the second direction. A second terminal shaft penetrating the center of the second terminal (430) in the first direction may be positioned between a pair of second tap members.

[0142] A second gasket (431) may be installed between the cap plate (410) and the second terminal (430). The second gasket (431) electrically insulates the cap plate (410) and the second terminal (430) and can block moisture or foreign substances from entering between the cap plate (410) and the second terminal (430).

[0143] The second gasket (431) according to the present embodiment may be formed from an insulating material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) rubber, etc. The second gasket (431) may be fixed between the cap plate (410) and the first terminal (420) by press fitting, injection molding, bonding, etc.

[0144] The cap assembly (400) according to the present embodiment may further include a vent hole (440) and a vent (450).

[0145] The vent hole (440) according to the present embodiment may be formed to have the shape of a hole that penetrates both sides of the cap plate (410) vertically along the first direction. The vent hole (440) may function as a configuration that provides a path for flames, gas, smoke, etc. formed inside the case (100) to be discharged to the outside of the case (100) in the event of thermal runaway of the secondary battery due to overcurrent, etc. The vent hole (440) may be positioned between the first terminal (420) and the second terminal (430). The cross-sectional shape of the vent hole (440) can be designed to be various shapes, such as elliptical, circular, or polygonal.

[0146] The vent (450) is installed in the vent hole (440) and can be opened and closed in conjunction with changes in the internal pressure of the case (100). That is, the vent (450) can close the vent hole (440) during normal operation of the secondary battery to prevent the electrolyte inside the case (100) from leaking out of the case (100) or the moisture, foreign substances, etc. from entering the case (100). The vent (450) can open the vent hole (440) during thermal runaway of the secondary battery to induce flames, gas, smoke, etc. formed inside the case (100) to be discharged to the outside of the case (100).

[0147] The vent (450) according to the present embodiment may be formed to have a shape approximately like a plate. The vent (450) may be fixed to the cap plate (410) by various types of joining methods, such as welding, bolting, or snap joining. The vent (450) may be placed inside the vent hole (440), or it may be placed facing the vent hole (440) along the first direction on the upper or lower side of the cap plate (410).

[0148] The thickness of the vent (450) parallel to the first direction may be smaller than the thickness of the cap plate (410). Accordingly, the vent (450) can be easily ruptured or broken when the internal pressure of the case (100) increases. The vent (450) may include a notch formed concavely on the inner side of the vent (450) so as to be preferentially broken when the internal pressure of the case (100) increases.

[0149] The cap assembly (400) according to the present embodiment may further include an electrolyte injection port (460) formed by penetrating the cap plate (410) and on which a sealing plug may be installed. The electrolyte injection port (460) may be positioned at a predetermined distance from the vent hole (440) in the second direction or in the direction opposite to the second direction. The electrolyte injection port (460) may be positioned between the first terminal (420) and the second terminal (430).

[0150] The cap assembly (400) according to the present embodiment may further include an insulating plate (470).

[0151] An insulating plate (470) may be placed between the cap plate (410) and the electrode assembly (200). The insulating plate (470) can insulate the cap plate (410) and the electrode assembly (200) by preventing direct contact between the cap plate (410) and the electrode assembly (200). The insulating plate (470) can fix the position of the electrode assembly (200) inside the case (100). The insulating plate (470) can prevent the electrode assembly (200) from being damaged if the cap plate (410) is deformed inwardly into the case (100) due to external impact or the like.

[0152] The insulating plate (470) according to the present embodiment may be positioned facing the electrode assembly (200) along a first direction inside the case (100). That is, the electrode assembly (200), the insulating plate (470), and the cap plate (410) may be positioned sequentially along the first direction. The insulating plate (470) may be fixed to the inner surface of the case (100) by various types of joining methods such as snap-fitting, welding, bolting, and bonding. The insulating plate (470) may be in contact with one surface of the electrode assembly (200) to which the first tab member (310) and the second tab member (320) are extended. The insulating plate (470) may be formed from an insulating material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) rubber, etc.

[0153] The first connecting member (500) may be disposed between the electrode assembly and the cap assembly (400). The first connecting member (500) may be connected to the first terminal (420) and the first tab member (310).

[0154] The first connecting member (500) may be extended in a third direction so as to be inserted in a third direction into the first connecting hole (312) of the stacked first tab member (310). As illustrated in FIG. 2, the first connecting member (500) may function as a configuration that electrically connects the first terminal (420) and the first tab member (310).

[0155] The first connecting member (500) may be formed of a conductive material. The first connecting member (500) may be formed of the same material as the first terminal (420).

[0156] The first connecting member (500) may include a first current collector (510) and a first current collecting plate (520). That is, the first current collector (510) is connected to the first terminal (420), and the first current collecting plate (520) can be inserted into and connected to the first connecting hole (312) of the first tap member (310).

[0157] The first current collector plate (520) may include a first portion (522) that is positioned on one side relative to the center and electrically connected to the first terminal (420), and a second portion (524) that is positioned on the other side relative to the center of the first connecting member (500) and inserted into the first connecting hole (312).

[0158] The first current collector plate (520) is bent with respect to the center of the first current collector plate (520) so that the first part (522) can be folded over the upper part of the second part (524).

[0159] The second connecting member (600) may be disposed between the electrode assembly and the cap assembly (400). The second connecting member (600) may be connected to the second terminal (430) and the second tab member (330).

[0160] The second connecting member (600) may be extended in a third direction so as to be inserted in a third direction into the second connecting hole (332) of the stacked second tap member (330). As illustrated in FIG. 2, the second connecting member (600) may function as a configuration that electrically connects the second terminal (430) and the second tap member (330).

[0161] The second connecting member (600) may be formed of a conductive material. The second connecting member (600) may be formed of the same material as the second terminal (430).

[0162] The second connecting member (600) may include a second current collector (610) and a second current collecting plate (620). That is, the second current collector (610) is connected to the second terminal (430), and the second current collecting plate (620) can be inserted into and connected to the second connecting hole (332) of the second tap member (330).

[0163] The shape of the second current collector plate (620) is the same as that of the first current collector plate (520), so a detailed description is omitted.

[0164] FIG. 6 is a front view schematically showing a tab member of an electrode assembly according to a first embodiment of the present invention.

[0165] A first connection hole (312) into which a first connection member (500) can be inserted may be formed in the first tab member (310). The shape of the first connection hole (312) may be formed in a square or circular shape.

[0166] Additionally, a second connection hole (332) into which a second connection member (600) can be inserted may be formed in the second tab member (330). The shape of the second connection hole (332) may be formed in a square or circular shape, similar to the first connection hole (312).

[0167] Each first tap member (310) and second tap member (330) is formed as a pair and can be branched and extended in a pair so that the first current collector plate (520) is inserted into the first connection hole (312) of the first tap member (310), and can be branched and extended in a pair so that the second current collector plate (620) is inserted into the second connection hole (332) of the second tap member (330).

[0168] These first tab member (310) and second tab member (330) can be formed in various shapes. This can increase the size of the first tab member (310) and second tab member (330) and improve heat generation performance.

[0169] FIG. 7 is a first modified example schematically showing a tab member according to a first embodiment of the present invention, FIG. 8 is a second modified example schematically showing a tab member according to a first embodiment of the present invention, and FIG. 9 is a third modified example schematically showing a tab member according to a first embodiment of the present invention.

[0170] Referring to FIGS. 7 to 9, the first tap member (310) may be formed as a single unit to form a single or multiple first connection holes (312), and the second tap member (330) may be formed as a single unit to form a single or multiple second connection holes (332).

[0171] This allows the resistance to be reduced by increasing the size of the first tap member (310) and the second tap member (330), thereby improving heat dissipation performance. At this time, the first current collection plate (520) and the second current collection plate (620) may be formed in multiple branches to correspond to the number of first connection holes (312) or second connection holes (332) formed in the first tap member (310) and the second tap member (330).

[0172] FIG. 10 is a drawing showing the connection between the first connecting member (500) and the first tap member (310) according to the first embodiment of the present invention.

[0173] Referring to FIG. 10, the first connecting member (500) according to the present embodiment can be inserted into the first connecting hole (312) of the first tap member (310). By welding the upper part of the first tap member (310) in the state shown in FIG. 10, the first tap member (310) and the first connecting member (500) can be electrically connected.

[0174] The connection between the first connecting member (500) and the first tap member (310) can be strengthened in various ways.

[0175] FIG. 11 is a first modified example showing the connection between the first connecting member (500) and the first tap member (310) according to the first embodiment of the present invention.

[0176] Referring to FIG. 11, the first connecting member (500) and the first tap member (310) according to the present embodiment can be more firmly joined by compaction of the first tap member (310).

[0177] That is, the first tap member (310) and the first connection member (500) can be firmly joined by compacting the first tap member (310) while the first connection member (500) is inserted into the first connection hole (312) of the first tap member (310), and the first tap member (310) and the first connection member (500) can be electrically connected by welding the upper part of the first tap member (310) after compaction is completed.

[0178] FIG. 12 is a second modified example showing the connection between the first connecting member (500) and the first tap member (310) according to the first embodiment of the present invention.

[0179] Referring to FIG. 12, the first connecting member (500) according to the present embodiment can be firmly bonded by filling the first connecting hole (312) of the first tap member (310) with a conductive bond (b). In this way, the first tap member (310) and the first connecting member (500) are fixed by filling with the conductive bond (b), and the first tap member (310) and the first connecting member (500) can be electrically connected by welding the upper part of the first tap member (310).

[0180] FIG. 13 is a schematic diagram showing the formation process of a secondary battery according to the first embodiment of the present invention, and FIG. 14 is a schematic diagram showing the completed state of a secondary battery according to the first embodiment of the present invention.

[0181] Referring to FIGS. 1 to 14, the cap assembly (400) is supplied in an inverted state, and the first connecting member (500) provided in the cap assembly (400) is inserted into the first connecting hole (312) of the first tab member (310), and the first tab member (310) and the first connecting member (500) are electrically connected to each other by welding, and the first current collector plate (520) is bent around the center and folded to wrap around the first tab member (310), so that the cap assembly (400) can be positioned on the upper part of the electrode assembly. In this way, the cap assembly (400) and the electrode assembly (200) are modularized, and the modularized cap assembly (400) and the electrode assembly (200) can be inserted into a case (100) to form a secondary battery.

[0182] Since the connection between the second connecting member (600) and the second tap member (330) is the same as the connection between the first connecting member (500) and the first tap member (310), the connection between the first connecting member (500) and the first tap member (310) is explained instead.

[0183] FIG. 15 is a first modified example schematically showing a first connecting member (500) according to a first embodiment of the present invention, and FIG. 16 is a second modified example schematically showing a first connecting member (500) according to a first embodiment of the present invention.

[0184] Referring to FIG. 15, the first current collection plate (520) of the first connecting member (500) according to the present embodiment may be formed such that the first portion (522) is bent vertically from the second portion (524) with respect to the center.

[0185] This allows the first portion (522) of the first connecting member (500) to be supplied in a state where it is already bent from the second portion (524), thereby facilitating the bending operation of the first current collection plate (520) and reducing the error in the bending position since it is already bent.

[0186] Referring to FIG. 16, the first connecting member (500) according to the present embodiment may be composed of a plurality of thin tabs. When the first current collector plate (520) is formed with a thick thickness, cracking and sufficient bending may occur, but by being composed of a plurality of thin tabs, the bending operation can be facilitated.

[0187] Hereinafter, a secondary battery according to the second embodiment of the present invention will be described.

[0188] The secondary battery according to the present embodiment may be configured to differ only in the connection structure between the first connecting member (500) and the first tab member (310) according to the first embodiment of the present invention.

[0189] Accordingly, in describing the secondary battery according to the present embodiment, only the connection structure of the first connecting member (500) and the first tab member (310), which is different from the secondary battery according to the first embodiment of the present invention, will be described.

[0190] For the remaining components of the secondary battery according to this embodiment, the description of the secondary battery according to the first embodiment of the present invention may be applied as is.

[0191] FIG. 17 is a schematic diagram showing the formation process of a secondary battery according to a second embodiment of the present invention, and FIG. 18 is a schematic diagram showing the completed state of a secondary battery according to a second embodiment of the present invention.

[0192] Referring to FIGS. 17 and 18, an auxiliary tab (700) that reinforces the rigidity of the welded portion may be further provided on the upper part of the first tab member (310) according to the present embodiment.

[0193] The auxiliary tab (700) can be formed in a flat shape to improve the rigidity of the welded area. More specifically, the first tab member (310) forms a narrow welded area by the first connection hole (312), and by welding together with the auxiliary tab (700), the deterioration of the weld quality can be prevented.

[0194] Referring to FIG. 17, the cap assembly (400) is supplied in an inverted state, and the first connecting member (500) provided in the cap assembly (400) is inserted into the first connecting hole (312) of the first tap member (310), and an auxiliary tap (700) is stacked on top of the first tap member (310) while the first tap member (310) is inserted into the first connecting hole (312). Subsequently, the auxiliary tap (700), the first tap member (310), and the first connecting member (500) can be electrically connected to each other by welding performed on the upper surface of the auxiliary tap (700). Then, the first current collector plate (520) is bent around the center and folded to wrap around the first tap member (310), so that the cap assembly (400) can be positioned on top of the electrode assembly (200). In this way, the cap assembly (400) and the electrode assembly (200) are modularized, and the modularized cap assembly (400) and the electrode assembly (200) are inserted into a case (100) to form a secondary battery.

[0195] Since the connection between the second connecting member (600) and the second tap member (330) is the same as the connection between the first connecting member (500) and the first tap member (310), the connection between the first connecting member (500) and the first tap member (310) is explained instead.

[0196] FIG. 19 is a modified example showing the connection between the first connecting member (500) and the first tap member (310) according to the second embodiment of the present invention.

[0197] Referring to FIG. 19, the present embodiment may include a detachment prevention part (800) that prevents the first connecting member (500) inserted into the first connecting hole (312) from detaching.

[0198] The anti-detachment member (800) may include a hook formed at the end of the first connecting member (500) and connected to the auxiliary tab (700). That is, a hook is formed at the end of the first connecting member (500) inserted into the first connecting hole (312), and the auxiliary tab (700) stacked on the upper part of the first tab member (310) is connected to the hook, thereby preventing the first connecting member (500) from detaching from the first connecting hole (312).

[0199] Although not shown, a through hole may be formed in the auxiliary tab (700) to which a hook, which is an anti-detachment part (800), is attached.

[0200] Hereinafter, a secondary battery according to the third embodiment of the present invention will be described.

[0201] The secondary battery according to the present embodiment may be configured to differ only in the connection structure between the first connecting member (500) and the first tab member (310) according to the first embodiment of the present invention.

[0202] Accordingly, in describing the secondary battery according to the present embodiment, only the connection structure of the first connecting member (500) and the first tab member (310), which is different from the secondary battery according to the first embodiment of the present invention, will be described.

[0203] For the remaining components of the secondary battery according to this embodiment, the description of the secondary battery according to the first embodiment of the present invention may be applied as is.

[0204] FIG. 20 is a schematic diagram showing the formation process of a secondary battery according to the third embodiment of the present invention, and FIG. 21 is a schematic diagram showing the completed state of a secondary battery according to the third embodiment of the present invention.

[0205] Referring to FIGS. 20 and 21, an auxiliary tab (700) that reinforces the rigidity of the welded portion is provided on the upper part of the first tab member (310) according to the present embodiment, and a conductive bond can be applied to the upper surface of the auxiliary tab (700) to form an adhesive portion (710).

[0206] The auxiliary tab (700) can be formed in a flat shape to improve the rigidity of the welded area. Additionally, an adhesive portion (710) made of a conductive bond is formed on the upper surface of the auxiliary tab (700) to strengthen the electrical connection during lamination by bending the first connecting member (500).

[0207] Conductive bonds are adhesives capable of transmitting electricity or heat, and may contain conductive particles such as silver (Ag), copper (Cu), carbon (C), and graphene. In other words, conductive bonds can maintain electrical and thermal conductivity while having adhesive properties.

[0208] Referring to FIG. 20, the cap assembly (400) is supplied in an inverted state, and a first connecting member (500) provided in the cap assembly (400) is inserted into the first connecting hole (312) of the first tap member (310), and an auxiliary tap (700) is stacked on top of the first tap member (310) while the first tap member (310) is inserted into the first connecting hole (312). Subsequently, the auxiliary tap (700), the first tap member (310), and the first connecting member (500) can be electrically connected to each other by welding performed on the upper surface of the auxiliary tap (700). Then, a conductive bond is applied to the upper surface of the auxiliary tab (700) to form an adhesive portion (710), and the first current collector plate (520) is bent around the center and folded to wrap around the first tab member (310), so that the cap assembly (400) can be positioned on the upper part of the electrode assembly (200). In this way, the cap assembly (400) and the electrode assembly (200) are modularized, and the modularized cap assembly (400) and electrode assembly (200) are inserted into a case (100) to form a secondary battery.

[0209] Since the connection between the second connecting member (600) and the second tap member (330) is the same as the connection between the first connecting member (500) and the first tap member (310), the connection between the first connecting member (500) and the first tap member (310) is explained instead.

[0210] Hereinafter, a method for manufacturing a secondary battery according to one embodiment of the present invention will be described.

[0211] FIG. 22 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0212] Referring to FIGS. 1 to 22, a method for manufacturing a secondary battery may include a connection hole forming step (S100), a connection step (S200), a welding step (S300), and a bending step (S400).

[0213] The connection hole forming step (S100) involves forming a connection hole in a tap member extending from the electrode assembly (200), wherein a first connection hole (312) is formed in the first tap member (310) and a second connection hole (332) is formed in the second tap member (330).

[0214] The first connection hole (312) and the second connection hole (332) can be formed through a notching process for forming the first tap member (310) and the second tap member (330).

[0215] A first tab member (310) formed on a first electrode (210) and a second tab member (330) formed on a second electrode (220) can form an electrode assembly (200) by stacking the first electrode (210) and the second electrode (220), thereby stacking the first tab member (310) and the second tab member (330).

[0216] The connection step (S200) involves inserting a connecting member connected to a terminal of the cap assembly (400) into a connecting hole, so that the first connecting member (500) is connected through the first connecting hole (312) of the first tap member (310) and the second connecting member (600) is connected through the second connecting hole (332) of the second tap member (330).

[0217] More specifically, the first current collecting plate (520) of the first connecting member (500) can be inserted into the first connecting hole (312), and the second current collecting plate (620) of the second connecting member (600) can be inserted into the second connecting hole (332).

[0218] At this time, the connection step (S200) may further include a bond filling step (S210) in which a conductive bond (b) is filled into the first connection hole (312) and the second connection hole (332) while the first current collector plate (520) is inserted into the first connection hole (312) and the second current collector plate (620) is inserted into the second connection hole (332).

[0219] Additionally, the connection step (S200) may further include a compaction step (S220) in which the tap member is compacted while the connection member is inserted into the connection hole. More specifically, the connection can be firmly established by compacting the first tap member (310) and the second tap member (330) while the first current collector plate (520) is inserted into the first connection hole (312) and the second current collector plate (620) is inserted into the second connection hole (332).

[0220] In this embodiment, the bond filling step (S210) and the compaction step (S220) may be omitted, and either the bond filling step (S210) or the compaction step (S220) may be performed selectively.

[0221] The welding step (S300) electrically connects the terminal and the tap member by welding the connecting member and the tap member while the connecting member is inserted into the connecting hole, and more specifically, the first tap member (310) and the first connecting member (500), and the second tap member (330) and the second connecting member (600) can be electrically connected.

[0222] At this time, an auxiliary tab (700) may be provided to improve the rigidity of the welded area. That is, after the auxiliary tab (700) is stacked on top of the first tab member (310) and the second tab member (330), the upper part of the auxiliary tab (700) is welded to electrically connect the auxiliary tab (700), the first tab member (310), and the first connecting member (500), and electrically connect the auxiliary tab (700), the second tab member (330), and the second connecting member (600).

[0223] In this embodiment, an auxiliary tap (700) is provided to prevent a decrease in welding quality, and the auxiliary tap (700) may be removed and welded directly from the upper part of the tap member.

[0224] After the welding step (S300), a conductive bond can be applied to the upper surface of the auxiliary tab (700) to form an adhesive portion (710).

[0225] The adhesive portion (710) can improve the electrical connection reliability of the first tab member (310) and the first connecting member (500), and the second tab member (330) and the second connecting member (600) when performing the bending step (S400) described later.

[0226] The bending step (S400) involves bending the center of the connecting member so that the cap assembly (400) is positioned on the upper part of the tab member, and the first part (522) that is bent with respect to the center of the tab member and connected to the terminal can be folded over the upper part of the second part (524) inserted into the connecting hole.

[0227] More specifically, the first current collector plate (520) and the second current collector plate (620) are bent around the center and folded to wrap around the first tab member (310) and the second tab member (330), so that the cap assembly (400) can be positioned on the upper part of the electrode assembly (200). In this way, the cap assembly (400) and the electrode assembly are modularized, and the modularized cap assembly (400) and the electrode assembly (200) can be inserted into a case (100) to form a secondary battery.

[0228] Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0229] Therefore, the technical scope of protection of the present invention should be determined by the following patent claims. Explanation of the symbols

[0231] 100 : Case 110 : Bottom part 120 : Front 130 : Rear 140: First side section 150 : Second side 160 : Opening 200 : Electrode assembly 210 : First electrode 211: First active material layer 212: First Unclear Part 220 : Second electrode 221 : Second active material layer 222 : Second Unclear Part 230 : Separator 310 : First tab member 312: 1st connection hole 330 : Second tab member 332 : 2nd connection hole 400 : Cap assembly 410 : Cap Plate 420 : 1st terminal 421: First gasket 430 : Second terminal 431 : Second gasket 440 : Vent hole 450 : Vent 460 : Electrolyte inlet 470 : Insulation plate 500 : First connecting member 510 : Entire 1st House 520 : First current collector plate 522 : Part 1 524 : Part 2 600 : Second connecting member 610 : Entire 2nd volume 620 : Second current collector plate 700 : Secondary tab 710 : Adhesive part 800 : Anti-detachment part

Claims

Claim 1 A secondary battery characterized by comprising: a case; an electrode assembly disposed inside the case and having a first electrode and a second electrode; a first tab member connected to the first electrode and extending from the electrode assembly; a cap assembly disposed facing the electrode assembly and having a first terminal and a second terminal; a first connection member electrically connecting the first terminal of the cap assembly and the first tab member; and a first connection hole formed in the first tab member to allow the first connection member to be inserted. Claim 2 A secondary battery according to claim 1, characterized in that the first tab member is formed of a pair spaced apart on one side with respect to the center of the first electrode. Claim 3 A secondary battery according to claim 1, wherein the first tab member is formed on one side based on the center of the first electrode, and the first connection hole is formed in plurality in the first tab member. Claim 4 A secondary battery according to claim 1, wherein the first connecting member comprises: a first portion disposed on one side with respect to the center of the first connecting member and electrically connected to the first terminal; and a second portion disposed on the other side with respect to the center of the first connecting member and inserted into the first connecting hole, wherein the first connecting member is bent with respect to the center of the first connecting member so that the first portion is folded over the upper part of the second portion. Claim 5 A secondary battery according to claim 4, characterized in that the second portion is welded to the first tab member while inserted into the first connection hole. Claim 6 A secondary battery according to claim 4, characterized in that the first tab member is compacted while the second portion is inserted into the first connection hole. Claim 7 A secondary battery according to claim 4, characterized in that a conductive bond is filled inside the first connection hole while the second portion is inserted into the first connection hole. Claim 8 A secondary battery according to claim 4, wherein the first portion is formed by bending vertically from the second portion. Claim 9 A secondary battery according to claim 4, characterized in that an auxiliary tab is further provided on the upper part of the first tab member to reinforce the rigidity of the welded portion. Claim 10 A secondary battery according to claim 9, characterized in that a conductive bond is applied to the upper surface of the auxiliary tab. Claim 11 A secondary battery according to claim 9, characterized by including a detachment prevention member that prevents the detachment of the first connecting member inserted into the first connecting hole. Claim 12 A secondary battery according to claim 11, wherein the above-mentioned anti-detachment member is a hook formed at the end of the above-mentioned first connecting member and connected to the above-mentioned auxiliary tab. Claim 13 A secondary battery according to claim 1, wherein the first connecting member is composed of a plurality of thin tabs. Claim 14 A secondary battery according to claim 1, characterized by comprising: a second tab member connected to the second electrode and spaced apart from the first tab member; a second connecting member electrically connecting the second terminal of the cap assembly and the second tab member; and a second connecting hole formed in the second tab member to allow the second connecting member to be inserted. Claim 15 A method for manufacturing a secondary battery, characterized by comprising: a connection hole forming step of forming a connection hole in a tab member extending from an electrode assembly; a connection step of inserting a connection member connected to a terminal of a cap assembly into the connection hole; a welding step of welding the connection member and the tab member while the connection member is inserted into the connection hole to electrically connect the terminal and the tab member; and a bending step of bending the center of the connection member so that the cap assembly is positioned on top of the tab member. Claim 16 A method for manufacturing a secondary battery according to claim 15, wherein the connection step comprises a bond charging step of charging a conductive bond inside the connection hole while the connection member is inserted into the connection hole. Claim 17 A method for manufacturing a secondary battery according to claim 15, wherein the connection step further includes a compaction step in which the tab member is compacted while the connection member is inserted into the connection hole. Claim 18 A method for manufacturing a secondary battery according to claim 15, wherein the welding step comprises providing an auxiliary tab on the upper part of the tab member and welding the upper part of the auxiliary tab so that the auxiliary tab, the tab member, and the connecting member are welded. Claim 19 A method for manufacturing a secondary battery according to claim 18, characterized in that, after the welding step, a conductive bond is applied to the upper surface of the auxiliary tab. Claim 20 A method for manufacturing a secondary battery according to claim 15, wherein the bending step is characterized in that a first portion connected to the terminal is bent with respect to the center of the tab member and folded over the upper portion of the second portion inserted into the connection hole.

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